This invention relates to an apparatus for cleaning magnetic recording tape and more particularly to an apparatus which is designed to be employed in conjunction with a video tape recorder to remove foreign particles from the face of the tape.
A clean video magnetic tape is desirable in order to obtain good picture quality and to reduce the wear of the playback and recording head of the video tape machine. Under normal use, the magnetic tape will become contaminated with debris such as dust, dirt, body salts, food particles, cigarette ashes, old oxide, backing materials, etc. These build-up of unwanted materials cause "drop-outs". These drop-outs either result in a poor picture quality or no picture at all in the area of the drop-outs.
It has been common in the past to employ a machine separate from the recording machine to clean the magnetic tape. On a regular basis, the video tape is removed from the recording machine and placed upon the separate cleaning machine and the tape is cleaned. Naturally, there is a substantial additional expense required in order to have available the cleaning machine. If one does not have a cleaning machine, the video tape can be transported to a service organization whose sole purpose is to clean magnetic tape. This also requires a substantial periodic expense.
Previously, such cleaning machines have frequently employed the use of metallic cleaning devices such as a metal scraper which frequently is in the form of a conventional razor blade. These type of cleaning metal blades are not satisfactory since the blade itself leaves deposits of metal particles on the tape. These metal particles produce problems during read-out and also are subject to a chemical reaction with the coating material of the tape. The breakdown of the metal is enhanced by the high heat factor generated due to the friction between the moving tape and the metal cleaning blade. The breakdown of the metal is particularly prevalent with steel, which is softer than many of the oxide coatings of the magnetic tape. These blades, as they are worn, produce uneven edges which is capable of producing scratches and grooves within a magnetic tape. Further, the metal blades are not capable of being polished to a keen edge and will not take steep clearance angles. As a result, it is impossible to get a good cutting edge with the use of a metal blade.
Previously, it has been known to employ the use of a monocrystalline material to perform the removal of the contaminants from a magnetic tape. Previously, there has been no consideration given as to the granular pattern formed within the monocrystalline block. By being made aware of the grain pattern within the block, certain sharpened edges of the block have the capability of lasting for a longer period of time by reason of being oriented in a particular manner in view of the grain pattern.
Further, there has been no known tape cleaning block which is designed to be placed directly upon an existing machine designed for the recording and playback of magnetic tapes, thereby completely eliminating the separate machine that has been necessary in the past in order to effect cleaning of magnetic tape.